Preparation method of polyurethane and silicon dioxide aerogel composite material

Abstract

The invention provides a preparation method of a polyurethane and silicon dioxide aerogel composite material, which comprises the following steps: mixing polyether polyol, polyol and a catalyst to obtain a mixture; jointly foaming the mixture with silicon dioxide aerogel, isocyanate, a foaming agent and silicone oil to obtain a foamed material; and carrying out heat preservation and curing treatment on the foaming material to obtain the composite material. The silicon dioxide aerogel and the polyurethane are mixed, uniform and dense small holes are formed in the prepared polyurethane silicon dioxide aerogel composite material, the heat insulation performance of the polyurethane material is effectively improved, the composite material which is lower in heat conductivity coefficient and has certain mechanical strength is prepared, the cost of the used raw materials is low, and the method is suitable for industrial production. And the method is convenient to operate and very easy to industrialize.

Description

Technical Field

[0001] The invention relates to the technical field of plastics, and in particular to a method for preparing a composite material of polyurethane and silicon dioxide aerogel. Background Art

[0002] Polyurethane foam materials have strong thermal insulation capabilities, and the thermal conductivity is usually less than 0.2W / (K·m). They are widely used in the automotive field, mainly including hard, soft, and semi-hard foams. In addition, polyurethane also has excellent properties such as anti-aging, chemical corrosion resistance, and wear resistance, but its fire resistance is poor. In recent years, with the continuous improvement of my country's requirements for automobile energy conservation, higher requirements have been put forward for the thermal insulation capacity of polyurethane.

[0003] Silica aerogel is a nanoporous lightweight material with high porosity, pores filled with gaseous dispersion medium, and ultra-low density. Its special nanoporous structure gives it a very low thermal conductivity coefficient of about 0.013W / (K·m), which is much lower than pure polyurethane. However, for general silica aerogel materials, due to their extremely high porosity, their strength and toughness are relatively low, making them difficult to use as fillers.

[0004] After searching, it was found that the Chinese invention patent with application publication number CN110396166A discloses a polyurethane foam with good thermal insulation and its preparation method. The raw materials include 30-70 parts of polyester polyol, 15-35 parts of polyether polyol, 10-25 parts of aerogel, 5-10 parts of foaming agent, 0.5-2 parts of foam stabilizer, 0.5-1 part of catalyst, 0.75-1.6 parts of water, and 65-75 parts of polyisocyanate; the aerogel includes silica aerogel and alumina / silicon dioxide aerogel. It is well known that aerogel has poor dispersibility and it is difficult to obtain a mixture with good dispersibility. However, the number of aerogels used in CN110396166A is large, which is difficult to prepare.

[0005] The Chinese invention patent with application publication number CN118772367A discloses a polyurethane composite foam material, a preparation method thereof, and an application in batteries. The polyurethane composite foam material includes component A and component B; the component A includes the following raw materials in parts by weight: 30-50 parts of polyol, 4-5 parts of cross-linking agent, and 0.2-0.4 parts of foaming agent; the component B includes the following raw materials in parts by weight: 45-55 parts of isocyanate and 1-2 parts of hydrophobic aerogel. This patent focuses on the use of hydrophobic aerogel for new energy batteries, and the application scenarios are limited. Summary of the invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a method for preparing a polyurethane and silica aerogel composite material, so as to provide a polyurethane and silica aerogel composite material with lower thermal conductivity and certain mechanical strength.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] The present invention provides a method for preparing a composite material of polyurethane and silicon dioxide aerogel, the method comprising:

[0009] mixing the polyether polyol, the polyol and the catalyst to obtain a uniform mixture;

[0010] foaming the mixture together with silica aerogel, isocyanate, a blowing agent and silicone oil to obtain a foamed product;

[0011] The foamed material is subjected to heat preservation and aging treatment to obtain a composite material.

[0012] Optionally, the polyol is triisopropanolamine.

[0013] Optionally, the catalyst is dibutyltin dilaurate.

[0014] Optionally, the polyether polyol, the polyol and the catalyst are mixed to obtain a mixture, wherein the mass ratio of the polyether polyol, the polyol and the catalyst is (35-45): (1.5-3.5): (0.30-0.56).

[0015] Optionally, the polyether polyol, polyol and catalyst are mixed to obtain a mixture, wherein: the mixing method is stirring, the stirring speed is (1500-2500) r / min, and the stirring time is at least 10 minutes, in order to achieve a uniform mixing effect.

[0016] Optionally, the blowing agent is dichloroethylene fluoride.

[0017] Optionally, the mixture is foamed together with silica aerogel, isocyanate, a blowing agent and silicone oil, wherein the mass ratio of the mixture, the silica aerogel, the isocyanate, the blowing agent and the silicone oil is (40-50):(0.32-0.96):(50-70):(7-13):0.1.

[0018] Optionally, the mixture is foamed together with silica aerogel, isocyanate, foaming agent and silicone oil, including: stirring the mixture with silica aerogel, isocyanate, foaming agent and silicone oil, and after the reactant turns white, pouring the foamed material into a mold and foaming it statically.

[0019] Optionally, the stirring speed is (1000-1200) r / min, the stirring time is (9-12) s, and the static foaming time is (1-2) min, so as to achieve uniform distribution of the silica aerogel in the mixture.

[0020] Optionally, the foamed material is subjected to heat preservation and aging treatment, wherein: after the volume of the foamed material no longer changes, it is placed in a heat preservation furnace and aged at (100-110)°C for (30-40) min, and then stored at room temperature for (65-75) h to achieve uniform and stable foaming.

[0021] The present invention utilizes polyurethane synthetic raw materials and silica aerogel to carry out a joint foaming reaction. During the foaming process, a uniform and fine micro-nano structure is generated inside the composite material, thereby ensuring that the composite material has a lower thermal conductivity than pure polyurethane and has sufficient mechanical strength.

[0022] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0023] The present invention mixes silica aerogel with polyurethane, and the prepared polyurethane silica aerogel composite material has uniform and fine pores formed inside, which effectively improves the thermal insulation performance of the polyurethane material, and prepares a composite material with lower thermal conductivity and certain mechanical strength. The thermal conductivity of the composite material prepared by the present invention can be reduced to 0.0325W / (K·m), and the compression strength can reach 0.3133MPa, which can meet industrial needs and has wide applicability. The raw materials used in the present invention are all commonly used chemical products, with low cost, convenient operation, and very easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0025] Figure 1 The internal structure comparison between the composite material and pure polyurethane in Example 1 of the present invention is shown, wherein: (a) is pure polyurethane, and (b) is the composite material;

[0026] Figure 2 The internal structure of the composite material in Example 2 of the present invention at different magnifications is shown, wherein: (a) is 100 times, and (b) is 200 times;

[0027] Figure 3 The internal structure of the composite material in Example 3 of the present invention is shown. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0029] Example 1

[0030] The chemical components shown in Table 1 were configured, and samples were obtained by co-foaming according to the preparation process of polyurethane-silica aerogel composite materials.

[0031] Table 1 Chemical composition mass of Example 1

[0032]

[0033]

[0034] The polyurethane-silica aerogel composite and pure polyurethane were characterized by scanning electron microscopy. Figure 1 shown.

[0035] From the comparison Figure 1 (a) and (b) show that the pores of pure polyurethane are randomly distributed and uneven in size, with a larger average pore size. When 0.64g of silica aerogel is added, a continuous hexagonal uniform pore structure is formed inside the polyurethane composite material, with a smaller average pore size.

[0036] Example 2

[0037] The chemical components shown in Table 2 were configured, and samples were obtained by co-foaming according to the preparation process of polyurethane-silica aerogel composite materials.

[0038] Table 2 Chemical composition mass of Example 2

[0039] Components Mass(g) Polyether polyols 40 Isocyanate 70 Silica Aerogel 0.96 Foaming agent 13 Polyols 2.5 catalyst 0.42 Silicone oil 0.1

[0040] Using scanning electron microscopy, the polyurethane-silica aerogel composites were characterized, such as Figure 2 shown.

[0041] from Figure 2 It can be seen that when the silica aerogel content in the composite material component increases, the pores gradually rupture and collapse, the pore size becomes no longer uniform, and the average pore diameter becomes larger.

[0042] Example 3

[0043] The chemical components shown in Table 3 were configured, and samples were obtained by co-foaming according to the preparation process of polyurethane-silica aerogel composite materials.

[0044] Table 3 Chemical composition mass of Example 3

[0045] Components Mass(g) Polyether polyols 40 Isocyanate 50 Silica Aerogel 0.32 Foaming agent 7 Polyols 2.5 catalyst 0.42 Silicone oil 0.1

[0046] Using scanning electron microscopy, the polyurethane-silica aerogel composites were characterized, such as Figure 2 shown.

[0047] from Figure 3 It can be seen that when the silica aerogel content in the composite material component decreases, the pores gradually break and collapse, the pore size becomes uneven, and the average pore size becomes larger. When the silica aerogel content exceeds the range in the above embodiment of the present invention, it is not conducive to improving the thermal insulation performance and / or strength of the composite material.

[0048] The thermal conductivity and compressive strength test of the composite material, the test process is as follows:

[0049] Thermal conductivity test of polyurethane silica aerogel composites

[0050] The prepared silica aerogel polyurethane composite samples were tested with a hotdisk thermal conductivity analyzer according to ISO22007-2008 standard, and each sample was tested three times. The sample was cut into two square prisms with a side length of 100mm×100mm and a thickness of 30mm. The circular chip probe used for testing was sandwiched between the two prepared composite materials and completely wrapped. According to the size of the test sample and the estimated thermal conductivity, the test probe radius was selected as 14.61mm. The test time was set to 80 seconds, the test power was 0.015W, and the room temperature was 25 degrees Celsius. The thermal conductivity of the sample will be calculated by the software provided by the thermal conductivity meter.

[0051] Compression Strength Test of Polyurethane Silica Aerogel Composites

[0052] According to the standard of GB / T8813-2008, at least three specimens are tested for each sample. During the test, the sample is cut into a regular quadrangular prism with a compression surface of 50mm×50mm and a thickness of 30mm. The test is carried out on a universal testing machine (model: Instron3300universal) with a compression speed of 2.5mm / min.

[0053] The samples obtained according to Examples 1 to 3 were tested for thermal conductivity and compressive strength. Through calculation, the average thermal conductivity and compressive strength of the polyurethane silica aerogel composite material are shown in Table 4.

[0054] Table 4 Thermal conductivity and compressive strength test results

[0055]

[0056]

[0057] As can be seen from Table 4, the thermal insulation performance of Example 1 is improved by 20.3% compared with pure polyurethane, while the mechanical compression strength is improved by 12.0%; for Example 2, its thermal insulation performance is improved by 9.0% compared with pure polyurethane, while the mechanical compression strength is improved by 5.8%; and for Example 3, its thermal insulation performance is improved by 7.6% compared with pure polyurethane, while the mechanical compression strength is improved by 5.8%.

[0058] Comparative Example

[0059] The mass fractions of polyether polyol, isocyanate, silica aerogel and foaming agent in the composite material are 50, 70, 0.96 and 3 respectively. The thermal conductivity coefficient of the final composite material obtained by the same preparation method as the above embodiment is 0.04127 W·(K·m) -1 , lower than the thermal conductivity of pure polyurethane.

[0060] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or variations within the scope of the claims, which does not affect the essence of the present invention. The above preferred features can be used in any combination without conflicting with each other.

Claims

1. A method for preparing a composite material of polyurethane and silica aerogel, characterized in that: include: mixing a polyether polyol, a polyol and a catalyst to obtain a mixture; foaming the mixture together with silica aerogel, isocyanate, a blowing agent and silicone oil to obtain a foamed product; The foamed material is subjected to heat preservation and aging treatment to obtain a composite material.

2. The method for preparing the polyurethane and silica aerogel composite material according to claim 1, characterized in that: The polyol is triisopropanolamine.

3. The method for preparing the polyurethane and silica aerogel composite material according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate.

4. The method for preparing the composite material of polyurethane and silica aerogel according to claim 1, characterized in that: The polyether polyol, the polyol and the catalyst are mixed to obtain a mixture, wherein the mass ratio of the polyether polyol, the polyol and the catalyst is (35-45): (1.5-3.5): (0.30-0.56).

5. The method for preparing the composite material of polyurethane and silica aerogel according to claim 1, characterized in that: The polyether polyol, polyol and catalyst are mixed to obtain a mixture, wherein the mixing method is stirring, the stirring speed is (1500-2500) r / min, and the stirring time is at least 10 minutes.

6. The method for preparing the composite material of polyurethane and silica aerogel according to claim 1, characterized in that: The foaming agent is ethylene dichloride.

7. The method for preparing the composite material of polyurethane and silica aerogel according to claim 1, characterized in that: The mixture is foamed together with silica aerogel, isocyanate, a blowing agent and silicone oil, wherein the mass ratio of the mixture, the silica aerogel, the isocyanate, the blowing agent and the silicone oil is (40-50):(0.32-0.96):(50-70):(7-13):0.

1.

8. The method for preparing the composite material of polyurethane and silica aerogel according to claim 1, characterized in that: The mixture is foamed together with silica aerogel, isocyanate, foaming agent and silicone oil, including: stirring the mixture with silica aerogel, isocyanate, foaming agent and silicone oil, and after the reactant turns white, pouring the foamed material into a mold and foaming it statically.

9. The method for preparing the composite material of polyurethane and silica aerogel according to claim 8, characterized in that: The stirring speed is (1000-1200) r / min, the stirring time is (9-12) s, and the static foaming time is (1-2) min.

10. The method for preparing the polyurethane and silica aerogel composite material according to claim 1, characterized in that In, The foamed material is subjected to heat preservation and aging treatment, wherein: the foamed material is aged at a temperature of (100-110)°C for (30-40) minutes, Then store at room temperature for (65-75) hours to mature.

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